The presentation of modern graphics on a display (e.g., electronic device or monitor) often involves displaying a sequence (e.g., a series) of “screens” on the display. For example, an electronic display monitor (e.g., with a cathode ray tube or a plasma flat-panel display) may display a rectangular arrangement of pixels, any one or more of which may change as each screen is displayed. A display may present one screen at a particular time and present another screen at another particular time. Accordingly, a current screen may be presented at a current time (e.g., now), while a previous screen may have been presented at a previous time (e.g., one minute ago or a day ago).